Homological dimensions of the amalgamated duplication of a ring along a pure ideal

The aim of this paper is to study the classical global and weak dimensions of the amalgamated duplication of a ring $R$ along a pure ideal $I$

The analysis of Iran universities’ 2003-2004 entrance examination to detect biased items

Item bias or differential item function (DIF) refers to the situation in which the probability of correct responses to an item for examinees with equal ability measured by test but belong to different groups are not equal. The existence of bias in items decreases the validity of the test. In this study the range of item difficulty among surveyed groups, has been used as a method for detecting the item bias in Persian literature subtest as part of the Entrance Examination to Universities of Iran in 2003-2004. For this purpose, report cards of 5000 (each group of 1000 examinees) participants in this examination from three provinces i.e. Yazd, Azerbaijan Sharghi and Kurdistan as sample groups were analyzed using the computerized program, BILOG-MG. Out of 25, two items, numbers 9 and 10 showed bias between gender groups and both were in favour of female group and were identified as biased items. Of this number, four items numbers 2, 7, 9, and 12 showed bias among linguistic groups

Effect of MHD on Nanofluid flow, Heat and Mass Transfer over a Stretching Surface Embedded in a Porous Medium

The steady, laminar, mixed convection, boundary layer flow of an incompressible nanofluid past over a semi-infinite stretching surface in a nanofluid –saturated porous medium with the effects of magnetic field and chemical reaction is studied. The governing boundary layer equations (obtained with the Boussinesq approximation) are transformed into a system of nonlinear ordinary differential equations by using similarity transformation. The effects of various physical parameters are analyzed and discussed in graphical and tabular form. Comparison with published results is presented and we found an excellent agreement with it. Mainly, it found firstly, that an increase in magnetic parameter M decreases both the local Nusselt number and local Sherwood number. Secondly, a great order of the chemical reaction increases the Nusselt and Sherwood numbers

GUIDED WAVE PROPAGATION IN THERMAL MEDIA THROUGH THE SEMI ANALYTICAL FINITE ELEMENT METHOD

In this paper, the issue of the estimation of wave propagation characteristics in thermal media is dealt with. A formulation, named the Thermal Semi Analytical Finite Element, based on the semi analytical finite element approach coupled with the thermal effect is offered. Temperature variations affect the mechanical properties of the waveguide. The question of dispersion curves and group velocities is studied. This study is expected to be of use in the sensitivity analysis of guided waves for wave propagation in thermal environment. Comparisons between numerical and analytical results are given to show the effectiveness of the proposed approach

Radiological findings in Behçet disease

Between 5 and 30% of patients with Behçet's disease will present neurological signs during the course of their illness. In order to evaluate the radiological signs on neuro-behçet disease, we studied consecutive patients in whom the diagnosis of this disease was retained, and who referred from January 2004 to December 2011 to the neurology and internal medicine departments in Mohammed VI universitary hospital in Marrakesh. Using 1.5T magnetic resonance imaging (MRI) with axial and coronal T2- weighted, axial Fluid Attenuated Inversion Recovery (FLAIR), pre- and post-contrast axial, coronal and sagittal T1-weighted sequences. The final number of patients in whom the diagnosis criteria of behçet disease were fulfilled and in whom an MRI was performed was 68 cases. Among these patients, 52 had parenchymal form of neuro-behçet with abnormalities in the MRI, 12 had vascular form and 4 patients had normal MRI. The brainstem, cerebral white matter, basal ganglia, internal capsule, thalamus and spinal cord were involved in forty four, thirty one, thirty, twenty nine, seventeen and four patients, respectively. The cerebral peduncle was the brainstem structure mainly involved with thirty cases followed by the pons with, twenty cases. Midbrain involvement interested forty patients. Brainstem atrophy was seen in eighteen cases. Finally, control MRI were obtained in four cases only, and showed changes in lesions size and shape

Hybrid extendable linear actuators: design and applications

There are many types of different actuators in the field of robotics. For applications where a linear displacement is required, a linear extendable actuator would be the method of choice. The hybrid class of extendable actuators possesses unique features making it suitable for many applications where the soft and rigid types fall short. However, there has not been a clear designation and classification of extendable linear hybrid actuators in the literature. This paper addresses this matter and provides the first overview of the hybrid class of extendable actuators. The paper performs a categorization and characterization of this class of extendable linear actuators based on their method of operation as well as the inherent unique features separating them from the rest. The paper contains five sections, and three sub-sections pertaining to the different categories of Hybrid actuators, and their applications. New research in this field continues to add features to this class of actuators through improvements and added capabilities